Production of carbon dioxide ice



May 19 1931. R DONALD 1,806,240

PRODUCTION OF CARBON DIOXIDE ICE Filed Nov. 1, 1928 2 Sheets-Sheet 1 JAMES RKHADDSON DONALD. INVENTQR.

By AT TOQN EY5.

May 19, 1931. J. R. DONALD PRODUCTION OF CARBON DIOXIDE ICE Filed Nov.

IAMEB RICHAEDSON DONALD ATTOQ NEY5.

Patented May 19, 1931 UNITED STATES PATENT FF PRODUCTION OF CARBON DIOXIDE ICE Application. filed November 1, 1928.- Serial No. 316,518.

This inventionrelates to the production of ice from carbon dioxide gas and has for its object the provision of a simple, economical process whereby a substantially dense ice is formed without the use of excessively high pressures.

In the processes heretofore used carbon dioxide gas is compressed at comparatively high ,pressures of approximately 60-100 or no more atmospheres and cooled to liquefy the same, after which it is allowed to expand into a chamber with the formation of snow, which is then compressed to form a block, The ice so formed is made up of the comre pressed, finely divided particles of snow and is thus somewhat porous or granular in character. In the present process the carbon dioxide gas is compressed and the temperature is re 2 duced below that at which the gas is converted to the liquid phase at the pressure employed. The reduction of the temperature makes it possible to liquefy the gas at much lower pressures. This temperature varies with the pressure, some of the corresponding temperatures andpressures being substantially as follows:

Temperature Pressure Plus 10 6.--; 44 atmospheres 0 C atmospheres Minus 10 C 26 atmospheres v Minus 30 U 13 atmospheres Minus C 7 atmospheres 35 Minus 65 C 4 atmospheres The pressure on the liquefied carbon dioxide is then released to allow the mass to boil and internally cool itself until the re maining portion of the liquid is directly conce verted to the solid form.

The accompanying drawings illustrate diagrammatically three forms of apparatus in which the process may be carried out.

Figure 1 illustrates an apparatus in which as the cooling is effected in the liquid chamber:

Figure 2 illustrates an apparatus in which an exchanger is employed:

Figure 3 illustrates a larger form of apparatus. a

5 In the drawings, 1 represents astorage vessel for carbon dioxide, 2 a compressor con nected therewith and discharging into a con-- tainer 3. The latter has a removable bottom 4, illustrated as hinged at 5 and held tightly closed by a suitable device 6, and a spaced surrounding jacket 7 likewise provided with a readily removable bottom 8 hinged at 9 and securely closed at 10. In the pipe 11 is a two-way valve 12 to which is connected the pipe 13 which leads to the storage vessel 1. 69 14: represents any suitable device for circulating a refrigerant about the container 3.

In operation the CO gas is compressed by means of the compressor 2 to, for example, 26 atmospheres, and at the same time the temperature in the chamber 3 is reduced to minus 10 C. by the circulation of a suitable refrigerant such as, for example, ammonia or cold air. This changes the gas to liquid. The valve 12 is then adjusted to disconnect the compressor and the reduction of pressure causes the liquid to expand and escape as gas into the storage tank, at the same time cooling the gas therein. This release of gas is continued until the remaining liquid has been cooled by expansion to the point of solidification. The valve 12 is then closed and the refrigerant removed when the closures 8 and 4 are opened to release the block of ice. A jet of air at room temperature or steam may be impinged momentarily upon the walls of the chamber 3 to readily release the block.

In Figure 2, A is a heat exchanger connected with the compressor 2 and the refrigeration device'l and discharging into the 35 chamber 3, the walls of which are suitably insulated as by the vacuum chamber B. The two-way valve 12 is located in the discharge pipe from the exchanger and is likewise connected with the vessel 1.

In the operation of this device the CO gas is subjected to a pressure of, say, 26 atmospheres and the temperature in the exchanger A is reduced to minus 10 C. by circulation of any suitable refrigerant, whereby the gas is liquefied and fills the chamber 3. The pressure is then released by adjusting the valve 12 as before and by internal cooling caused by the expansion the remaining liquid is solidifiedoto form a substantially dense 1G0 i 20 and 20 block of ice. The block is removed by opening the closure 4 as'before.

The liquid carbon dioxide is thus converted directly to the solid producing a relatively 5 compact mass by the application of moderate, pressure.

3 In Figure 3 which shows an apparatus for employing he invention to produce solid CO on a larger scale, 13 indicates a supply tank which is kept filled with CO gas from any suitable source. The gas from tank 13 is forced by means of a pump orcompressor 14 through a pipe 15 to a'heat exchanger 16. The gas is cooled and liquefied by its passage through the tubes of the exchanger 16, and the liquefied gas flows by way of a pipe 17 to a distributing valve 18. In the illustrated position of valve 18 the liquid gas flows through pipes 19 and 19 to chambers 20 The valve 18 is also connected by pipes 19 and 19 to chambers 20 and'20 respectively. The chambers 20 to 20 are also respectively connected by pipes 21 ,21", 21"v and 21 to a four-way valve 22, the outlet of za'which is connected of the exchanger 16. The shell of the exchanger is also connected by a pipe 24 tothe suction of the pump 4. v

The open bottoms of chambers 20 to 20 are closed by any suitable hinged or removable covers 25 to 25 and are heat-insulated by any convenient means such as evacuated 2 spaces 26? to' 26. v In the position shown, chamber 20 is just beginning to be filled with liquid CO Chamber 20 is half-filled. Chamber 20 contains its full charge of liquid CO and is just beginning to evaporate through pipe 21. This evaporation causes the liquid in chamber 20 to solidify, and the evaporated gas passes out through-pipe 21, valve 22, pipe 23 and in passing through the exchan er 16 cools and liquefies the inc ming gas fiowing through the exchanger t bes. The'evaporated gas then leaves the exchanger and passes by way ofthe pipe 24 to the suction of the pump 14. Both valves 1 8and 22 are closed with respect to chamber 20 the cover 25 is opened and the blockof solid CO is being removed.

When the block has been removed from chamber 20 and the cover 25 is closed, this chamber is ready to be refilled with liquid; chamber 20 is ready to discharge its block of ice; chamber 20 is filled with liquid and ready to expand, and chamber 20 is halffilled with liquid, and these actions may be performed by rotating the valves one-quarter revolution in a clockwise direction. The operation is therefore cyclic and semi-automatic, and the apparatus forms a closed circuit so that-waste of material is eliminated. a To facilitate removal of the solid CO the lowerparts of the ice chambers may be pro vided with jackets with which air or steam by a Pipe 23 to the shell 0 I oxide which comprises compressing and coolcommunicate, these inlet pipes 27 to 27 pipes being controlled by valves 28 the stems of which are in the path of movement of the covers 25 to 25 so that when a cover is opened air or steam is automatically admitted to the corresponding jacket. The.

air or steam leaves the jackets through pipes communicating with an outlet pipe 29.

It will be understood that the invention is not limited to any particular number of chambers 20, which number may be varied according to the desired I claim: 1. A process of producing solid carbon dioxide which comprises compressing and cooling the gas to liquefy it, conveying the li uecapacity of the plant.

fied gas to a closed, heat-insulated cham er, Y

simultaneously evaporating the liquefied gas in another previously filled heat-insulated chamber and employing the resulting gas to effect the first mentioned cooling, and simultaneously removing from another heat-insulated chamber a block of solidified carbon dioxide. I

2. A process of producing solid carbon diing the gas to'liquefy it, filling certain of a series of heat-insulated chambers. with said liquefied gas, expanding the liquefied gas contained in another, previously filled chamber of said series, removing a block of solidified carbon dioxide from another'of said series of chambers, and successively and repeatedly performing said steps of filling, expanding and removing in each of the said chambers.

In testimony whereof I have afiixed my signature.

J. R. DONALD. 

